Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The amino acid sequence of the cysteine-containing peptide was determined in two different manners. 1) Chicken pepsin was covalently coupled via its SH-group to Thiopropyl-Sepharose 6B, subjected to peptic digestion and cysteinyl peptides, generated by multiplicity of peptic attack on the sequence ..-Tyr-Tyr-Cys-Asn-Phe-.. (marked by arrows), were eluted by 2-mercaptoethanol. 2) Systematic structure analysis of the tryptic-chymotryptic digest of chicken pepsinogen afforded peptide Tyr-Tyr-Cys-Asn-Phe-Asp-Gly-Ile-Leu-Gly-Leu, whose C-terminal part is highly homologous with other pepsins. These data permitted the cysteinyl residue to be assigned to position 115 (numbered according to hog pepsin A) in a relatively variable region. The same position is occupied by an alanyl residue in hog pepsin A and calf chymosin; this replacement can be considered conservative from the viewpoint of molecular volume.